Patients are expected to be moved back into parts of Wales' only children’s hospital by Thursday.
The Noah's Ark Children's Hospital for Wales was closed because of water damage yesterday due to torrential rain earlier in the week.
Eighteen children in total were moved to other child health areas.
Phil Barry, Directorate Manager for Child Health, said: “All the staff involved have been fantastic. Our priority has been to provide an environment and safe care to all those affected by the incident."
Work to determine the exact cause and to asses the extent of the damage to the higher floors will continue over the next few days.
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